A Baltimore hookup is when you hookup with your half sister or half brother but you don't know it at the time. That's because the two of you were never really sure who your father was.

That boy sure is slow. His parents must have been a Baltimore Hookup!

Keisha and I were done gettin busy, just laying in bed, when we discovered that we both had the same double jointed little fingers. I asked her if she knew her father. She said no but that she thought his name was Earl. I told her I didn't know mine either and that I thought my dad's name was Earl too. That's when we knew we had a Baltimore Hookup!